Cutting and drawing oil



Oct. 19, 1937. G. w. cuPlT, JR

CUTTING AND DRAWING OIL Filed Aprilv 2o, .1934

` [lnder/.19er

'Lew

For/denser' L Fece/'ver fecei ver INVENTOR George l1/- (0p/'2j A ATTORNEY Patented Oct. 19, 1.9537

PATENT ori-ICE CUTTING AND DRAWING on.

George W. Cupit, Jr., Woodside, N. Y., assigner to General Chemical Company, New York, N. Y., a corporation oi New York Application April 20, 41934, Serial No. 721,454

Claims.

This invention relates to improvements in the art of cutting and drawing metals and to oils for such purposes. More particularly, the invention is directed to cutting and drawing oils comprising 5 sulfur bearing oils derived from sludges 'formed in oil rening processes in which sulfuric acid is employed.

The principal object of the invention is directed to improvements in the cutting of metals and to the provision of high sulfur cutting and drawing ,oils and/or cutting and drawing oil bases for this purpose. The invention also aims to provide sulfur cutting and drawing oils or bases light in color and light bodied, and having a high sulfur content substantially all of which Vsulfur is in chemical combination. It is a further object of the invention to provide high sulfurcutting and drawing oils which are stable and do not become turbid, or deposit sulfur on standing.

In oil refining processes, involving treatment of petroleum distillate oils with sulfuric acid, large quantities o f Asludges ,are produced. When destructively decomposed by heating, these sludges form gas mixtures containing Water vapor and condensable hydrocarbon vapors, and gases such as sulfur dioxide, carbon dioxide, nitrogen and uncondensable hydrocarbons.

` It has been discovered that when sludge material, resulting from treatment with sulfuric acid 30 of relatively light hydrocarbon oil distillates containing substantial quantities of sulfur compounds, is dissociated preferably by destructive decomposition by heating to form a hot gas mixture containing hydrocarbon vapors and the gas mixture is cooled, for example to about normal temperature, an oily condensate is obtained which is a sulfur bearing oil possessing properties sought for in cutting and drawing oils. It has been discovered that these' oils are light colored, light ical combination, and which do not become turbid or deposit free sulfur on standing. y

A further appreciation of the objects and advantages of the invention may be hadfrom a consideration of the following description oi' the improved cutting and drawing oils and of methods for making the oils.` The accompanying drawing illustrates diagrammaticallyapparatus by which the improved cutting oils may be made. Referring to the drawing, I0 indicates the-com-f 'bustion chamber of a furnace adapted to burn coal, coke, oil, natural gas or other fuel. Mounted in chamber I0 is a decomposing kiln or retort II of any desirable, construction, for example a ilxed shell provided with suitable mechanism Such bodied, stable oils, high in sulfur in strong chemas a screw conveyor, not shown, to facilitate discharge of coke. A rotary retort may also be employed if desired. Preferably an externally heated kiln adapted to substantially exclude admission of air is used. One end of ykiln Il 5 communicates with a gas outlet I3, and the opposite end projects into a header I4 into which the solid residue of the decomposition of the acid sludge is continuously discharged. Header I4 empties into air-lock I 5 through which coke may be discharged without admitting air to the kiln. Acid sludges constituting sources of the improved cutting oils are run into the kiln from supply tank Il through a valve-controlled pipe I8. Gas outlet I3 is connected to kthe lower end of a cooler or condenser 20 of any suitable construction, either air or water cooled, and operated so as to reduce the temperature of the gas stream to substantially normal to condense the bulk of the water-vapor and a major portion of condensable hydrocarbons contained in the gas. Condensate from the cooler-drains into a collecting tank 2| through a pipe 22 having a liquid seal.

The gases uncondensed in cooler 20, containing principally sulfur dioxide, are discharged through gas line 23, and may be used as desired,

for example, in the manufacture of sulfuric acid.

Separator 2i may be a tank or vat large enough to permit continuous gravity separation of water and oil contained in the condensate discharged from condenser 20. The hydrocarbon oils of the condensate rise to the top of the mass in the separator, and may be withdrawn continuously or intermittently through pipe 25 discharging into a collecting tank 26. Water settling to the bot- 35 tom of the separator may be drawn off through pipe 21, controlled by Valve 28, and discharged to waste or otherwise disposed of.

The still 30, of any approved construction, may be externally heated by hot combustion gases generated in brickwork setting 3 I. Raw condensate from collecting tank 26 is run into the still through pipe 38, controlled by valve 39. Vapors generated in the still flow through line 4| to a condenser 43, the condensate of which drains through pipes 45 and 46, into receivers 50 and 5I.

Cutting oils of the invention may be made in apparatus such as illustrated in the drawing and described above by operating substantially as follows:

In producing the improved cutting oils, acid sludges which may be employed arethose resulting from sulfuric acid treatment of light distillate oils obtained from petroleum crudes containing sulfur. The acid sludges employed in making vare straight-run gasoline distillates containing about 0.15% sulfur or more, and cracked distillates averaging 0.25 to 0.30% sulfur orV more.

Sludge material, of the type indicated and which may have a titratable acidity ofA 40% to 60% expressed as HzSOli, is continuously fed into kiln Il from supply tank Il. The burners in furnace I0 are adjusted to preferably maintain within the kiln temperatures desirably not in excess of about 750 F., as above this temperature the sulfur oils of the present invention tend to be decomposed.' The preferred temperatures are about 250 F. at the sludge inlet end, andy about 500 to 600 F. at the coke outlet end of the kiln.

The sludge, gradually passed through the retort, is relatively gradually heated through the preferred temperature range and is dissociated by the action of heat, and the free and combined sulfuric acid of the sludge is reduced to sulfur dioxide by the hydrogen of the hydrocarbons and/or by the carbonaceous matter contained in the sludge.` The sludge material is thus dissociated, as by the destructive decomposition method indicated, with production of water vapor, and hydrocarbon vapors and sulfurqcompounds are formed. Residual coke is continuously discharged from the kiln through air-lock I5. The major part of the sulfur oils of the present invention are evolved by the time the sludge has reached a. temperature of S50-400 F.

The gas resulting from the decomposition of the sludge contains principally water vapor and sulfur dioxide, substantial amounts of conden- Asable hydrocarbons and sulfur compounds and smaller quantities of uncondensable hydrocar-` bons and gases lsuch as carbon dioxide, ca-rbon monoxide, and nitrogen. For example, the exit gas mixture of the retort may contain by volume about 50% water vapor, about 10% condensable hydrocarbon vapors and sulfur compounds,.the balance comprising sulfur dioxide, carbon dioxide, carbon monoxide, nitrogen, hydrocarbon gases and oxygen. As previously noted, according to afpreferred embodiment of the process for making the cutting oils of the invention, decomposition of sludges is effected in the kiln'substantially in the absence of oxygen. When so operating, formation of carbon dioxide is lessened, presumably because oxidation of hydrocarbons and burning of carbonaceous matter of the sludge is prevented.

` The hotgaseous and Vaporous products of decomposition of the sludge are discharged from the kiln and passed-through conduit I3 into -condenser 20 in which the gases are cooled to substantially normal temperatures. Cooling may be accomplished by circulating through the condenser Ain indirect heat exchange relation with the retort gas mixture any suitable cooling liquid or gas. In place of the condenser illustrated in the drawing, a Vertical tower having a spray head at the top v'for introduction of water may be employed'. In such cases, the retort gas mixture is'introduced intothe bottom of the tower and flows upwardly, intimately contacting and mingling with the downwardly directed spray of water fed in at the top of the tower. The amount of cooling water introduced is so controlled as to cool the exit gases leaving the top of the tower to about normal atmospheric temperatures.

During cooling of the retort gas mixture in the condenser 20, substantially all of the Water vapor and the major portion of the condensable hydrothe bottom of the separator 2| may be discharged from the system through pipe 21.

The oil collecting in tank 26 is an oil containing generally from about 3 to about 22% sulfur, apparently in strongchemical combination. It will be understood the sulfur content of this condensate may vary considerably in accordance with the characteristics of the .initial crude oils' and of the acid sludges produced on treatment of the hydrocarbon oll distillates with sulfuric acid. For example, an .acid sludge formed through sulfuric acid treatment of ay straight-run gasoline yielded an oil condensate ofA 12% by volume of the sludge, the condensate analyzing 14.8% sulfur. A cracked distillate sludge yielded 10% by volume of oil condensate having a sulfur content of 7.5%. In another instance, a cracked distillate averaging about 0.25

' to 0.30% sulfur produced on treatment with sulfuric acid a sludge which, on treatment in accordance with the present method, yielded 10.8% by volume of oil condensate analyzing 20.8% sulfur. i

By the present invention, it has been found that oils produced as described above are sulfurcontaining oilshaving properties rendering them particularly suited for use as cutting and drawling oils. The raw condensate recovered in tank 26 may, if desired, be used directly as a cutting or drawing oil. However, since the oil in this state contains .substantial quantities of foreign matter, such as coke dust and tars, and also a low boiling these substances." This may be done by distillation. For this purpose voils from tank `26 are run into still 30 through line 38. The distillation operation may be carried out in any suitable still, -f

preferably one provided with equipment for collecting separate fractions of distillate. `Distilla tion of the raw condensate is principally forV two purposes, first, to remove coke and tars from the oil, and second, to produce preferably two fractions, one having a relatively low boiling range and containing low ash point hydrocarbonsand another fraction having a higher boiling point range and constituting the preferred cutting and drawing oil of the invention. Distillation may be fraction of low flash point it is preferred to remove effected for example by external heating of still 30.

If desired,l-distillation of the crude condensate'I may also be accomplished at temperatures lower than those hereinafter mentioned by introducing live steam directly into the oilbody while externally heating the same. Distillation may also be effected, though possibly less desirably, by superheated live steam, using steam at slightly above atmospheric pressure and heated to say 22S-250 F.

before introduction into the oil. Vacuum distillation may be employed if desired.

Still 30 is operated to produce a first cut including all the oils distilling over at temperatures up to about 350 F. Vapors generated within this temperature range are liquefied in condenser 43, and are run into receiver 50. 'This relatively low boiling fraction may for example constitute approximately 20% by volume of the raw condensate.

fed into still 30. When removal of these low boiling fractions from the oil in still 30 is substantially complete, the temperature is raised to distill over oils having boiling points ranging from about 350 F. up to about 650 F. Vapors formed are condensed in cooler 43, and may be recovered in receiver I. This high boiling fraction may comprise for example about 70% by volume of the raw condensate introduced into still 30. Approximately of the original raw condensate withdrawn from tank 26 remains as a coke or asphalt residue in the. still.

The low boiling cut recovered in receiver 50 contains a slightly higher percentage of sulfur than the higher boiling fraction collected in receiver 5l. This low boiling cut while useful as a cutting oil has somewhat too low flash point for general use in cutting.

The preferred cutting and drawing oil of the invention is the higher boiling fraction recovered in reaction appears complete.

receiver 5|, and such oil may be so used directly as condensed in cooler 43. The oil, however, apparentlyfcontains substances such as pyridines and mercaptans somewhat unstable on standing. Accordingly, it is preferred to further treat the oil to stabilize the same and remove odors. This may f sulfuric acid, say about equal volume, and washed with water and alkali to remove traces of acid. It

is preferred to use aci-d of concentrationjnot in excess of about 60% HzSOl, since acid of this or less concentration, does not appear to have any appreciable effect on valuable sulfur compounds which should preferably be retainedin the product. If desired the oils may be stabilized by .using acid yof greater concentration, say up to about 93% H2SO4, in which case the amount of stronger acid employed should vnot desirably exceed about 7% by volume of the oil treated.

Treatment of the oil with either caustic alkali or sulfuric acid notably improves the odor and increases the stability of the oil. In some instances, it is preferred to subject the oil to treatment with both caustic alkali and sulfuric acid.

-In this case, after subjecting the oil to'the caustic soda treatment noted above, and removing the alkali extract, the oil is washed'with water to remo-ve -be washed with water to remove traces of acid,

and then brightened by blowing with air.

Strong sulfuric acid appears to extract at least vsome of the valuable sulfur compounds from both the' stabilized and unstabilized oils of the invention. It has been found in this connection that sulfuric acid stronger than about 70% and preferably about 93.2% (66 B.) will remove these sulfur compounds from the stabilized and unstabilized oils to form an acid sludge, and on hydrolysis of the acid sludges produced by such treatment practically the same volume of oil is recovered as was removed with the sulfuric acid and the oils recovered on hydrolysis are considerably higher in sulfur content than thel original oil. For example, on treating a heavy fraction stabilized by treatment with both caustic alkali and weak sulfuric acid, boiling approximately within the range S50-650 F. and containing about 11.6% sulfur, with about twice the volume of 93.2% sulfuricacid (66 B.), ther sulfur in the acid treated oil, after separation of the acid sludge formed was reduced to about 1.9%, and the sulfur content of the oil obtained after hydrolysis of th acid sludge was about 19%.

The heavy fraction stabilized, for` example as mentioned above, is a sulfur bearing mineral oil, light in color, light bodied, possessing no undesirable odor, and having a high sulfur content, substantially all of which is in strong chemical combination. It appears substantial amounts of the contained sulfur are present as alkyl sui'ldes and possibly also some disuldes. The sulfur ccntent varies from about 3 to about 22%. The oil on standing does not become turbid or deposit sulfur, a property highly desirable in a cutting oil. In this connection, sulfur oil of the invention has been subjected to a cold test, and it was found that at a temperature of 14 C. below zero, there is no separation of sulfur, the oil remaining uncloudedand of substantially unchanged viscosity. The oils of the invention are a light straw color, a feature which is particularly advantageous since there is no tendency for the oil to hide the work from observation during the cutting process. `The specicgravity of a representative oil is about 0.98, The viscosity is low, about 32 to 34 Saybolt at 100 F. This is a material advantage in cutting' and drawing operations. Prior cutting and drawing oils and bases are generally of high viscosity, and dilution with lighter oils is necessary to produce an oil having a viscosity suitable for working conditions. This dilution results in an oil having a lowered sulfur content. The oils of the invention are light4 bodied, flow easily and spread well, 'and hence may be used'directly as cutting and drawing oils if desired. Further, since the oils are readily miscible with heavier oils in all proportions and asthe sulfur content is high, the base oils of the invention may be compounded with non-sulfur mineral oils of requisite viscosity if desired to give compositions of desired characteristics and of high sulfur content.

As observed the oils of the invention may be used directly as cutting and drawing oils, or may be diluted with oils such as mineral or lard oil.

In one'instance, a hard chrome-manganese steel a 14% sulfur-bearing oilof the invention (stabifree sulfur, containing alkyl suldes, having va sulfur content not less than about 7.5% and not more than about 22% and formed by dissociating sludge material, resulting from sulfuric acid treatment of hydrocarbon distillate oils obtained from sulfur-containing crudes, with aid of heat to break up the sludge and under conditions to form a hot gas mixture containing water and hydrocarbon vapors, cooling the gas mixture to form a condensate comprising water and oil boiling at temperatures less than aboutl 650 F., separating oil and water, and recovering the oil.

2. A cutting and drawing oil base comprising a relatively light-bodied, light-colored, low viscosity sulfur oil, boiling substantially within the range 350 F. to 650 F., stablev at low temperature with respectv to sulfur deposition, substantially free of free sulfur, containing alkyl suldes, having a sulfur content not less than about 7.5% and not more than about 22% and formed by dissociating sludge material, resulting from sulfuric l acid ktreatment of hydrocarbon distillate oils obtained from sulfur-containing crudes, with aid of heat to break up the sludge and under conditions to form a hot gas mixture containing water and hy.- drocarbon vapors, cooling the gas mixture to :form a condensatefcomprising water and oil, separating oil and water, distilling the oil, and recovering tent not less than about 7.5% and not more than about 22% and formed by dissociating sludge ma'- terial, resulting from sulfuric acid treatment of light hydrocarbon distillate containing not less than about 0.15% sulfur, with aid of heat to break up the sludge and under conditions to form a hot gas mixture containing water and hydrocarbon vapors, cooling the gas mixture to form a condensate comprising water and oil boiling at temperatures less than about 650 F., separating oil and water, and recovering the oil.

4. A cutting and drawing oil base comprising a relatively light-bodied, light-colored, low viscosity sulfur oil, boiling substantially within the range 350 F. to 650 F., stable at low temperature with respect to sulfur deposition, substantially free of free sulfur, containing alkyl suldes, having a sulfur content not less than about 7.5% and not more than about 22% and formed by dissociating sludge material, resulting from sulfuric acid treatment of light hydrocarbon distillate containing not less than about 0.15% sulfur, with aid of heat to break up the sludge and under conditions to form a hot gas mixture containing water and hydrocarbon vapors, cooling the gas mixture to form a condensate comprising water and oil, separating oil and water, distilling the oil, and recovering as condensate a fraction boiling substantially within the range-350 F. to 650 F.

.5. A cutting and drawing oil base comprising a relatively light-bodied, light-colored, low viscosity sulfur oil, boiling at temperatures less than about 650 F., stable at low temperature with respectto sulfur deposition, substantially fre of free sulfur', containing'alkyl suldes, having a sulfur content not less than about '7.5% and not more than about 22% and formed by dissociating sludge material, resulting from sulfuric acid treatment of hydrocarbon distillate oils obtained from sulfur-containing crudes, with aid of heatv to break up the sludge and under .conditions to form a hot gas mixture containing water and hydrocarbon vapors, cooling the gas mixture to form a condensate comprising water and oil, separating oil and water, distilling the oil, and recovering as condensate oil boiling at temperatures less than about 650 F.

GEORGE W.' CUPIT, JR. 

